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ORIGINAL ARTICLE
Year : 2002  |  Volume : 18  |  Issue : 2  |  Page : 131-135
 

Helical CT angiography : A single imaging modality to evaluate a live renal donor


Department of Urology & Radiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India

Correspondence Address:
Anant Kumar
Department of Urology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow - 226 014
India
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Source of Support: None, Conflict of Interest: None


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   Abstract 

Introduction: Traditionally live related renal donors are evaluated with intravenous urography and renal ar­teriography. The computerized tomographic angiogra­phy (CTA) can offer a less invasive alternative to demonstrate the necessary anatomical and functional information. The present study evaluates the accuracy of helical CTA in depicting renal vascular and paren­chymal anatomy in live renal donors.
Patients and Methods: During March 1999 to March 2000 all live donors were evaluated with ultrasound ab­domen (USG), intravenous urography (IVU) and heli­cal CT (Picker PQ 5000, Picker Intl. USA). Renal arterial and venous anatomy was documented prospec­tively by a radiologist, which was correlated with the operative findings. Sensitivity, specificity and accuracy of CTA in depicting the renal vascular anatomy were assessed.
Results: Of 120 live donors evaluated, overall con­cordance between CT angiography and operative find­ings in delineating the arterial anatomy was found in 110 (91.6%) and venous in 116 (96.6%) donors. The sensitivity, specificity, and accuracy of CTA in depict­ing arterial anatomy was 91.6%, 98.2% & 91.6% and for venous anatomy was 96.7%, 90.0% and 97.0% re­spectively. We could not gather any additional informa­tion by performing intravenous urography.
Conclusions: Helical CT angiography, which is highly specific for arterial and venous anatomy as well as other anatomical and functional details, can become the single imaging modality for preoperative assessment of poten­tial donors in place of conventional angiography and IVU. CTA, being minimally invasive and cost effective, is well accepted by a normal healthy donor


Keywords: Live Renal Donors; Helical CT Angiography


How to cite this article:
Zaman W, Kumar A, Gupta R, Das S, Mandhani A, Srivastava A, Gupta A. Helical CT angiography : A single imaging modality to evaluate a live renal donor. Indian J Urol 2002;18:131-5

How to cite this URL:
Zaman W, Kumar A, Gupta R, Das S, Mandhani A, Srivastava A, Gupta A. Helical CT angiography : A single imaging modality to evaluate a live renal donor. Indian J Urol [serial online] 2002 [cited 2019 Nov 11];18:131-5. Available from: http://www.indianjurol.com/text.asp?2002/18/2/131/37613



   Introduction Top


Renal transplant has become the treatment of choice for the end stage renal disease. [1] Potential live renal donors un­dergo extensive preoperative evaluation which includes medical history, laboratory testing and radiological imaging. Assessment of renal anatomy is integral to the evaluation of living kidney donors. Ideally, the studies chosen should pro­vide vascular, parenchymal and ureteral anatomy and give us an idea about the renal function. Evaluation of anatomy is essential to ensure that the vascular anatomy is normal or can be adequately reconstructed. Additionally, preoperative decision, such as which kidney to remove, is often based upon the results of imaging studies. [2],[3]

Traditionally, imaging has included ultrasound abdomen, renal scan, excretory urography and conventional renal ar­teriography. Conventional angiography necessitates one day admission and 12 hrs post procedural observation, which causes inconvenience to potential donors and leads to addi­tional costs to the transplant program. [1],[4]

Helical CT is highly accurate and specific for the demon­stration of renal vascular anatomy. It provides essential ana­tomical information and can be an alternative to standard urography and ateriography. Helical CT being an out pa­tient procedure reduces cost of imaging and decreases mor­bidity associated with angiography. [5],[6],[7],[8]

In this prospective study we evaluate the accuracy of heli­cal CT angiography in depicting bilateral renal vascular, parenchymal and ureteral anatomy as well as the excretory pattern through a single imaging modality to evaluate live renal donors.


   Patients and Methods Top


The study involved a total of 120 potential kidney donors (M:F 35:85). Mean age of the donors was 41.5±9.2 (19-71) years. Initial clinical and laboratory assessment was done to ensure normal renal function. All live donors were evalu­ated with ultrasound abdomen (USG), intravenous urog­raphy (IVU) and helical CT angiography (CTA). Imaging studies were done on the donors according to a standard CT angiographic protocol, that is early arterial phase scan­ning (14-20 sec. Delay) & 5 mm 3 dimensional maximum intensity projection. CT was performed on a 4 th genera­tion slip ring technology CT scanner (Picker PQ 5000, Picker Intl. Cleveland, USA).

Renal arterial anatomy was evaluated for the number and location of arteries, accessory arteries, early branch­ing (within 1.5 cm of origin) and arterial stenosis. Venous anomalies, non-vascular abnormalities including paren­chymal and collecting system abnormality, calculus and non-renal abnormalities were noted. All images were in­terpreted by a single radiologist at our institution and reviewed by operating surgeon before harvesting the allo­graft.

The findings reported on helical CTA were used to se­lect the donor kidney. CTA findings were correlated with the IVU and operative findings and finally the sensitivity, specificity and accuracy of CTA in depicting the renal vascular, parenchymal and ureteral abnormalities were assessed.


   Results Top


Open donor neprectomy was performed in 104 poten­tial donors, while 16 donors underwent laparoscopic do­nor nephrectomy. Nephrectomy was performed on the left side in 104 and 16 on the right side in donors, after preoperative imaging showed complex vascular anatomy of the left kidney (3 or more renal artery) in 9 and several small cysts in right kidney in 4 donors.

Multiple renal arteries were present in 5 (4.1%); 2 ar­teries in 4 and 3 in one donor [Figure - 1]. Early branching of the main renal artery was seen in 7 cases (5.8%). Venous anomalies noted in 7 donors (5.8%), which consisted of retroaortic renal vein in 2 [Figure - 2], multiple veins in 3 and duplication of IVC in 2 cases [Figure - 3]. Similarly non-vas­cular renal abnormalities were identified in 15 cases (12.5%) [Figure - 4]. Renal calculi were seen in 2 and simple renal cysts were noted in 6 donors. A pelvic kidney was diagnosed via CT angiography (CTA) and harvested by open donor nephrectomy successfully. We could not gather any addition] information by performing intravenous urog­raphy. CTA has shown 100% accuracy for non-vascular lesions [Table - 1].

The overall concordance between CTA and preoperative findings in delineating the arterial anatomy was found in 110 cases (91.1%). 7 patients in whom CTA had shown single renal artery were found to have double renal artery preoperatively. In 5 patients CTA had missed a small aber­rant renal artery which was detected preoperatively. In 3 patients CTA had revealed suspicious renal artery stenosis at the hilum, but during surgery 2 cases didn't reveal any such abnormality. Renal arterial flow was confirmed on Doppler ultrasound. The sensitivity, specificity and accu­racy of CTA in detecting arterial anatomy were 91.6%, 98.2% & 91.6% respectively [Table - 2],[Table - 3].

There were 4 cases of discordance between CTA and surgery in the identification of venous anatomy. In two cases IVC duplication was diagnosed preoperatively, which was subsequently confirmed on surgery, but in one case it was missed. In one of them CT had revealed B/L double renal veins, but preoperatively the patient was found to have single renal vein on left side. In the other patient CT had missed the early branching of the left renal vein. The sensitivity, specificity and accuracy of CTA in delineating the venous anatomy were 96.7%, 90.0% & 97% respectively [Table - 2],[Table - 3].


   Discussion Top


The success of live renal donor transplantation depends on reliable characterization of renal morphology and func­tion. Renal angiography has long been considered the gold standard for the assessment of renal arterial anatomy. [5] But, it is invasive in nature and has risk of bleeding and arte­rial injury to the tune of 1.7%. [8],[9] It also requires post pro­cedural observation and causes discomfort to the patient. Moreover, arteriography doesn't provide parenchymal or venous anatomy and provides no 3-D image to the operat­ing surgeon. With the development of helical CT scanning and 3-D reconstruction, imaging of arterial and venous anatomy in three dimensions can be obtained. [1],[2],[3],[10]

In addition to identifying renal vascular and collecting system anatomy, preoperative assessment allows the sur­geon to look for vascular plaques and calcification, tumors, cysts and fibrodysplastic disease of the renal artery. Ab­dominal CT is the gold standard for the evaluation of parenchymal disease in the kidney. CT provides images of renal parenchymal anatomy and therefore identifies cysts and tumors. [1],[2],[3],[5],[11],[12]

The ability to define arterial, venous and renal paren­chymas in 3 dimensions is a distinct advantage for plan­ning an operation. The operating surgeon can accurately anticipate early branching and can plan the operative ap­proach by knowing the relationship of artery and vein, thereby decreasing the risk of vessel injury. [2],[13] It is specially more relevant during laparoscopic live donor nephrectomy.

Various studies comparing renal arterial anatomy im­age obtained by helical CT and arteriography found agree­ment in 89-96%. [1],[6] Our study demonstrated accuracy of CT scanning in defining renal arterial and venous anatomy in 91.6% and 97% respectively. CT angiography (CTA) has been reported as less sensitive for detecting the ve­nous anamolies. [2] We have found in our study that venous anomalies, such as multiple renal veins, retroaortic vein and circumaortic renal vein were easily identified by helical CT with 3-D reconstruction. Venous opacification and anatomi­cal delineation are better on CT than conventional arterio­graphy. [12] Preoperative identification of venous anomalies can result in shorter operative time and minimizes morbid­ity from unexpected vascular injury. [1]

Helical CTA has also been found to have an edge over urography and conventional arteriography in detecting nonvascular abnormalities such as benign and malignant masses, renal and ureteral calculi. parenchymal scarring and ureteral duplication. [1] Nonvascular abnormalities were found in 12.5% of donors in our study. In addition, CT enables evaluation of other abdominal and pelvic organs and may identify patients not suitable for kidney dona­tion. Recently few studies have indicated that CT has an accuracy rate sufficient to replace IVU and renal arteriog­raphy. [5],[6] CTA can be performed as a safe outpatient pro­cedure. [1],[3],[6],[7],[8],[11] There is 25% reduction in cost for imaging the potential donor with CTA versus standard renal arteri­ography and IVU (Rs.4500 vs. 6000).

Helical CTA with 3-D reconstruction has become the standard method of imaging in living donors at our insti­tution. It is simple, accurate, less expensive, convenient, less time consuming and well accepted by the patients.

We believe that CT angiography is the radiological pro­cedure of choice for assessment of renal anatomy in poten­tial living kidney donors and equally safe for graft retrieval. It can replace conventional angiography and intravenous urography for donor assessment. Based on this study, we can recommend ultrasonography as an initial screening modality followed by CTA. This way, we can avoid IVU and conventional angiography and can cut down the cost, hospitalization and morbidity of living renal donors.


   Conclusions Top


Helical CT angiography (CTA) is highly specific for ar­terial and venous anatomy as well as other anatomical and functional details and can become the primary imaging modality for preoperative assessment of potential donors in place of IVU and conventional angiography. There is greater patient acceptance and less morbidity associated with non-invasive nature of helical CT. It is also cost effective. It can thus be established as a single imaging modality to evalu­ate live donors.

 
   References Top

1.Kaynan AM. Rozenblit AM, Figueroa KI et al. Use of spiral com­puterised tomography in lieu of angiography for preoperative as­sessment of living renal donors. J Urol 1999; 161: 1769-1775.  Back to cited text no. 1    
2.Del Pizzo JJ. Sklar GN, You-Cheong JW et al. Helical computer­ized tomography arteriography for evaluation of live renal donor undergoing laparoscopic nephrectomy. J Urol 1999; 162; 31-34.  Back to cited text no. 2    
3.Slakey DR Florman. Lovretich J, Zarifian M. Cheng SS. Utility of CT angiography for evaluation of living kidney donor. Clin Trans­plant 1999; 13: 104-107.  Back to cited text no. 3    
4.Egglin TKP. O'Moore PV. Feinstein AR. Waltman AC. Complica­tion of peripheral arteriography; a new system to identify patients at increased risk. J Vase Surg 1995; 22: 787.  Back to cited text no. 4    
5.Cochran ST. Krasny RM, Danovitch GM et al. Helical CT angiog­raphy for examination of living renal donors. AJR 1997; 168: 1569-­1573.  Back to cited text no. 5    
6.Platt IF. Ellis JH. Korobkin M et al. Potential renal donors: com­parison of conventional imaging with helical CT. Radiology 1996: 198: 419-423.  Back to cited text no. 6    
7.Lionel G. Sebben RA. Costello P, Rao MM. The use of spiral com­puted tomographic angiography for the assessment of living kid­ney donors. AUST NZJ Surg 1999; 69: 217-219.  Back to cited text no. 7    
8.Tang S, Chan J. Tso WK et al. Helical computed tomographic angi­ography in the evaluation of Chinese living renal donors. BJU Int 1999, 83: 387-391.  Back to cited text no. 8    
9.Hessel SJ. Adams DF. Abrams HL. Complications of angiography. Radiology 1981: 138: 273-281.  Back to cited text no. 9    
10.Dachman AH, Newmark GM, Mitchell MT, Woodle ES. Helical CT examination of potential kidney donors. AJR 1998; 171: 193­-200.  Back to cited text no. 10    
11.Alfrey EJ, Rubin GD, Kuo PC et al. The use of spiral computerized tomography in the evaluation of living donors for kidney trans­plantation. Transplantation 1995; 59: 643.  Back to cited text no. 11    
12.Lerner LB, Henriques FH, Harris RD. Interactive 3-dimension com­puterized tomography reconstruction in evaluation of the living re­nal donors. J Urol 1999; 161: 403-407.  Back to cited text no. 12    
13.Pozniak MA, Balison DJ, Lee FT Jr et al. CT angiography of po­tential renal transplant donors. Radiographics 1998; 18: 565-587.  Back to cited text no. 13    


    Figures

  [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]
 
 
    Tables

  [Table - 1], [Table - 2], [Table - 3]



 

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    Abstract
    Introduction
    Patients and Methods
    Results
    Discussion
    Conclusions
    References
    Article Figures
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